Sample valve



Oct. 13, 1970 Filed Dec. 50, 1968 D M. VESPER SAMPLE VALVE 5Sheets-Sheet l 5 POWER GAS SAMPLE 20 I3 200 26 CARRIERI nu I30 VP VENT24 4c: PILOT VALVE I 20 Zlc: I 27 I '4 VENT Z l PROGRAMMERWCHROMATOGRAPHIC COLUMN DETECTOR F/G.

INVENTOR.

D. M. VESFER A 7' TORNEVS D. M. VESPER SAMPLE VALVE Oct. 13, 1970 5Sheets Sheet 2 Filed Dec. 30, 1968 FIG. 2

INVENTOR.

D. M.VESPER QM Q m ATTORNEYS United States Patent 3,533,295 SAMPLE VALVEDaniel M. Vesper, Bartlesville, Okla, assignor to Phillips PetroleumCompany, a corporation of Delaware Filed Dec. 30, 1968, Ser. No. 787,773Int. Cl. G01n l/JO US. Cl. 73-422 Claims ABSTRACT OF THE DISCLOSURE Asample valve comprises a valve body having a member secured theretothrough which a plurality of passages extend. Pressure operatedactuating means are carried by the valve body to block communicationbetween ends of the passages. A detachable valve cap, having passagestherethrough, is secured to the member so that passages in the cap andmember are in communication. External conduits can be connected to thepassages in the cap to communicate through such passages with passagesin the member.

It is common practice to analyze fluid mixtures by means ofchromatography. In a conventional chromatographic analyzer, a sample ofthe material to be analyzed is introduced into a chromatographic column,and carrier gas is thereafter passed through the column to elute theconstituents of the sample in sequence. In order to ob tain reproducibleresults, it is important that the sample volumes introduced into thecolumn remain constant. This can be accomplished by means of samplevalves which trap a predetermined volume of the sample in a loop anddeliver this trapped volume to the column when the valve is actuated. Amember of pneumatically operated diaphragm valves have been designedwhich are particularly effective for this purpose. One such valve isdescribed in U.S. Pat. 3,140,615.

The valve described in the foregoing patent, which is typical ofpneumatically operated sample valves, is usually provided with at leasteight conduits through which carrier gas, sample and power gas flow.Although such a valve is quite effective and reliable, it is sometimesdifiicult to remove the valve from the analyzer for cleaning and repairpurposes. This results from the fact that the analyzers are normallyassembled in temperature controlled housings of compact design and it isnecessary to break the eight conduit connections.

In accordance with the present invention, an improved pneumaticallyoperated sample valve is provided which can readily be removed from achromatographic analyzer. This is accomplished by means of a singleinlet fluid distribution cap which receives all of the externalconduits. The valve body is secured to this distribution cap by anyconvenient means, such as a plurality of screws, so that the valve bodycan be removed from the connecting conduits merely by removing the valvebody from the distribution cap. A replacement valve can then be attachedand the analyzer returned to service while the initial valve is beingcleaned or repaired. This structure greatly simplifies maintenance ofchromatographic analyzers.

In the drawing, FIG. 1 is a schematic representation of achromatographic analyzer having the sample valve of this inventionincorporated therein. FIG. 2 is a view, shown partially in section, ofthe sample valve employed in the analyzer of FIG. 1. FIG. 3 illustratesthe fluid distribution cap of the sample valve. FIG. 4 illustrates themanifold of the valve of FIG. 2. FIG. 5 is a perspective viewillustrating a portion of the valve mechanism. FIG. 6 is a view, shownpartially in section, of the fluid distribution cap of FIG. 3.

Referring now to the drawing in detail and to FIG. 1 in particular,there is shown a chromatographic column ice 10 which contains anysuitable packing or partitioning material. Carrier fluid is introducedthrough a conduit 11 which communicates with the first inlet port 11a ofa sample valve 12. A sample of fluid to be analyzed is introducedthrough a conduit 13 which communicates with an inlet port 13a of samplevalve 12. A conduit 14 extends from sample valve port 1411 to the inletof column 10. A conduit 15 extends from the outlet of column 10 to thefirst inlet of a differential detector 16. A portion of the carrierfluid is passed through a conduit 17 to the second inlet of detector 16.

Sample valve 12 is employed to introduce a predetermined volume ofsample selectively to the inlet of column 10. This is accomplished bymeans of a sample loop 20 which extends between ports 20a and 20a insuch a manner that the sample initially flows through the loop to fillthe interior thereof. After flowing through loop 20, the sample isvented through a conduit 21 which communicates with port 21a. Initially,carrier fluid flows from conduit 11 through valve 12 to conduit 14 andfrom there through column 10. When the valve is actuated, the flow ofcarrier fluid is diverted within the valve so as to pass through loop 20before entering outlet conduit 14. At the same time, the flow of sampleis vented. This results in the carrier fluid forcing the volume ofsample which originally occupied the loop out through conduit 14 tocolumn 10. Sample valve 12 is pneumatically operated and receivesoperating pressure from a pilot valve 22. Power gas is introduced intovalve 22 through an inlet conduit 23. A conduit 24 extends between thepilot valve and the sample valve. A conduit 25 extends between a vacuumpump 26 and sample valve 12 to facilitate operation of the sample valveunder certain conditions, as described hereinafter in greater detail.The operation of the sample valve can be controlled by a programmer 27which actuates pilot valve 22 at predetermined intervals.

Sample valve 12 is illustrated in detail in FIGS. 2 to 5. All of theexternal conduits illustrated in FIG. 1 enter a common fluiddistribution cap 30. As illustrated in FIGS. 2 and 3, this cap isprovided with eight inlet ports. The first six of these ports 11a, 13a,20a, 20a, 21a and 14a receive corresponding conduits of FIG. 1, aspreviously described. Ports 24a and 25a receive respective conduits 24and 25. Cap 30 is attached by screws 31 to a member 32. The first sixports of cap 30 are connected to respective internal passages in the cap(designated by corresponding b reference numerals) which terminate atthe lower face of the cap in a circular array. Member 32 is providedwith six vertical passages 11c, 13c, 20c, 20c, 21c and which are alignedwith corresponding passages in cap 30. O-rings 33 are positioned inrecesses in the upper face of member 32 to provide fluid tight sealsbetween the connected passages. Member 32 is also provided with twooutlet ports 24d and 25d which communicate with respective inlet ports24a and 25a. This communication is established by passages 24b and 25bin cap 30 and passages 24c and 250 in member 32. External conduits 24cand 252 serve to connect ports 24d and 25d with respective inletopenings 24 and 25f in a cylindrical housing member 34 of the samplevalve.

As illustrated in FIG. 2, the valve includes an upper plate 35 which issecured to manifold 32 by a plurality of set screws 36. First and seconddiaphragms 37 and 38 are positioned between the lower face of member 32and the upper face of plate 35. A sealing ring 39 surrounds thediaphragms. Plate 35 is secured to a sleeve 40 by means of a screw 41,and a lower plate 42 is secured to sleeve 40 by means of a screw 43.Cylindrical housing member 34 extends between plates 35 and 42. Pistons45 and 46 are disposed within housing 34 and are provided withrespective sliding sealing members 47 and 48 which engage the inner wallof housing 34.

A plurality of spring washers 49 are positioned between plate 42 andpiston 45 to urge the piston upwardly. The upper surface of piston 45 isadapted to engage three plungers 50, 51 and 52, see FIG. 5, when piston45 is moved upwardly. Piston 46 carries an annular member 53 which isadapted to engage plungers 54, 55 and 56 when member 53 is movedupwardly. A spring 57 is secured to plate 35 by a screw 58 so as toexert a downward force on piston 46. A plurality of pins 59, 60 and 61extend through common passages in plate 35, member 32 and cap to providealignment of these three members when the valve is assembled.

As illustrated in FIG. 5, plate is provided with six vertical passagesthrough which plungers 50, 51, 52, 54, 55 and 56 are free to move.Plungers 5'4, 55 and 56 are slightly longer than plungers 50, 51 and 52.The upper surface of plate 35 is provided with a plurality of recesses63 which connect the ends of adjacent vertical passages through theplate. Recesses 63 permit fluid flow between the lower ends of adjacentpassages in member 32 when the diaphragms are depressed into theserecesses. The movement of the diaphragms into the recesses is controlled by plungers 50, 51, 52, 54, 55 and 56. The upper end of plunger50 is located between passages 21c and 20c; the upper end of plunger 54is located between passages 13c and 21c; the upper end of plunger 51 islocated between passages 20c and 130; the upper end of plunger 7 55 islocated between passages 11c and 200; the upper end of plunger 52 islocated between passages 11c and 140; and the upper end of plunger 56 islocated between passages 20c and 14c. The raising and lowering of theplungers thus controls communication between adjacent passages in member32.

In the absence of power gas flowing to chamber 65 of FIG. 2, the valveis in the position illustrated. Washers 49 exert an upward force onpiston 45, the upper surface of which engages longer plungers 54, 55 and56 so that the sections of the diaphragm engaged by upper ends of theseplungers are moved to block respective recesses 63. Under thiscondition, the passages through member 32 are connected in the mannerillustrated by the solid lines in FIG. 1. Carrier gas flows from conduit11 to conduit 14 and into column 10. The sample fluid flows through loop20 and is vented through conduit 21. The pressures of these flowingfluids depress diaphragms 37 and 38 into the recesses which are notblocked by plungers 54, 55 and 56.

When pilot valve 22 is switched to the second position, power gas isintroduced into chamber 65 from conduit 24. As the pressure builds up inchamber 65, a force is exerted on piston 46 so that this piston risesagainst the force of retaining spring 57. Member 53 then engages shorterplungers 50, 51 and 52 to raise these plungers and the diaphragmsections immediately above these plungers. As the pressure continues toincrease in chamber 65, suflicient force is built up to overcome washers49 so that piston is moved downwardly. This retracts longer plungers 54,55 and 56. The combined plunger movements switch the valve to theposition illustrated by the dotted lines in FIG. 1. Carrier gas is thendirected through sample loop 20 to displace the volume originallytrapped therein into column 10. The incoming sample is vented throughconduit 21. Thus, the two positions of the value depend on theintroduction of power gas into chamber 65.

In a second embodiment of valve operation, vacuum pump 26 of FIG. 1 isconnected to port 25f of FIG. 2. This permits operation with carrier gasand/or sample fluid at substantially lower pressures because theapplication of vacuum to the under side of diaphragm 38 assists in thedownward displacement of the diaphragms in the absence of the passagesbeing blocked by plungers.

For a more detailed description of the construction and operation of thevalve illustrated in FIG. 2, reference is made to US. Pat. 3,140,615.

'The use of distribution cap 30 permits the valve to be disconnectedfrom the connecting conduits merely by removing screws 31. When thesescrews are removed, all of the valve assembly beneath cap 30 can beremoved as a single unit. This permits a second valve to be attached tothe existing conduits while the original valve is being cleaned orrepaired. As previously mentioned, this permits rapid servicing ofsampling valves in chromatographic analyzers and facilitatesconstruction because all of the connecting conduits are fastened to asingle unit, cap 30.

While this invention has ben described in conjunction with a presentlypreferred embodiment, it should be evident that it is not limitedthereto.

What is claimed is:

1. In a sample valve which includes a first member having first andsecond faces and a plurality of first passages extending between saidfaces in spaced relationship with one another, a valve body secured tothe first of said first member, a plurality of movable actuating meanscarried by said valve body and positioned so as to block communicationbetween the ends of selected ones of said first passages at the firstface of said first member when actuated, and pressure operated meanscarried by said valve body to operate said actuating means; theimprovement comprising a valve cap having a plurality of first ports anda plurality of second passages therein, the latter extending fromrespective ones of said first ports to respective locations spaced fromone another at a first face of said cap, said cap also having a secondport and a third passage extending from said second port to a point atthe said first face of said cap; means to secure said cap to said firstmember so that said first face of said cap engages said second face of.said first member and said second passages communicate with respectiveones of said first passages; and conduit means extending from said pointthrough said first member to said pressure operated means.

2. The valve of claim 1 wherein said conduit means comprises a thirdport in said first member spaced from the first face thereof, a fourthpassage in said first member extending from said point to said thirdport, and conduit means extending from said third port to an inlet ofsaid valve body which communicates with said pressure operated means.

3. The valve of claim 1 wherein said valve body contains a diaphragmwhich extends across said first face of said first member, and a chamberis formed in said valve body which is in communication with the side ofsaid diaphragm opposite said first face, and wherein said cap has athird port, a fourth passage extending from said third port to a secondpoint at said first face of said cap, and conduit means extending fromsaid second point through said first member to said chamber.

4. The valve of claim 1 wherein said cap and said first member are flatplates with said faces parallel to one another, said first passagesextend through said first member in directions generally perpendicularto said faces of said first member, and the ports in said cap are in theside thereof.

5. The valveof claim 1 wherein said means to secure said cap to saidfirst member comprises a plurality of screws which extend through saidcap into said first member.

References Cited UNITED STATES PATENTS 3,139,755 7/1964 Reinecke' et al.73-422 3,140,615 7/ 1964 Broerman 73-422 3,297,053 1/ 1967 McKinney.

3,384,122 5/1968 Harpman 137-62564 LOUIS R. PRINCE, Primary Examiner H.C. POST III, Assistant Examiner UNITED STATES PATENT OFFICE CERTIFICATEOF camEcTIm Patent No. 3,533,295 D. M. Vesper Dated Oct. 13, 1970 It iscertified that error appears in the above-identified patent and thatsaid .Letters Patent are hereby corrected as shown below:

Column 4, line 18, "race" has boon omitted between "first" and "of".

SIGNED MU REALEI' 6 Anew 3am M. Fletcher. in mm 1:. sum, :3. .AttestingOfficer flomissioner or Pat-ants

